我正在开发wpf应用程序。我在C＃中拥有Color对象的实例。假设我有一个红色Color对象的实例，即Color c = Color.FromArgb(255,255,0,0)现在假设我有一个值，范围从1到10.所以根据这个值，我想改变'c'对象的颜色。我希望浅红色为1，暗红色为10.浅红色变为暗，因为值从1增加。如何在C＃中为wpf应用程序执行此操作？能否请您提供我可以解决上述问题的任何代码或链接？
答案 0 :(得分：7)
您可以尝试简单地将红色，绿色和蓝色分量乘以某个系数。
public static Color ChangeLightness(this Color color, float coef)
{
return Color.FromArgb((int)(color.R * coef), (int)(color.G * coef),
(int)(color.B * coef));
}
或者，如果您想使用1到10之间的整数值而不是系数：
private const int MinLightness = 1;
private const int MaxLightness = 10;
private const float MinLightnessCoef = 1f;
private const float MaxLightnessCoef = 0.4f;
public static Color ChangeLightness(this Color color, int lightness)
{
if (lightness < MinLightness)
lightness = MinLightness;
else if (lightness > MaxLightness)
lightness = MaxLightness;
float coef = MinLightnessCoef +
(
(lightness - MinLightness) *
((MaxLightnessCoef - MinLightnessCoef) / (MaxLightness - MinLightness))
);
return Color.FromArgb(color.A, (int)(color.R * coef), (int)(color.G * coef),
(int)(color.B * coef));
}
答案 1 :(得分：1)
如果您有一定数量的值，那么Style DataTrigger怎么样？
https://www.google.co.uk/search?q=c%23+wpf+style+datatrigger
<Button>
<Button.Style>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding NameOfYourProperty}" Value="0">
<Setter Property="Background"
Value="#FF000000" />
</DataTrigger>
<DataTrigger Binding="{Binding NameOfYourProperty}" Value="1">
<Setter Property="Background"
Value="#FF110000" />
</DataTrigger>
<DataTrigger Binding="{Binding NameOfYourProperty}" Value="2">
<Setter Property="Background"
Value="#FF220000" />
</DataTrigger>
( etc ... )
</Style.Triggers>
</Style>
</Button.Style>
</Button>
然后，如果您需要重用该样式，那么您可以放入窗口/ usercontrol的<Resources>部分。
答案 2 :(得分：1)
假设您使用的滑块的最小值为1，最大值为10。您可以将值乘以25.5 (255 / max value)。然后，从最大值（255）中减去该答案，并将其用作红色值。
double newRedValue = 255 - (slider.Value * (255 / slider.Maximum));
int redValue = Convert.ToInt32(newRedValue);
Color c = Color.FromArgb(redValue ,255,0,0)
您可以使用常量值替换255 / slider.Maximum，因为它可能会保持不变。上面的公式将产生反效果，因此滑块值越低，红色的阴影越亮。当然，值为10将导致red为0，因此如果您不希望红色组件为低，则可以添加最小值。
答案 3 :(得分：1)
更清洁的解决方案是并置2个矩形：一个是你想要的颜色，另一个是黑色。
然后在黑色矩形上使用Opacity来暗化/淡化底层颜色。
看起来像是：
<Grid>
<Rectangle Fill="{Binding myColor}" />
<Rectangle Fill="Black" Opacity="{Binding colorModifierPercentage}" />
</Grid>
当然，colorModifierPercentage必须是介于0和1之间的数字，矩形可以是任意Shape。
答案 4 :(得分：0)
有an article about it at CodeProject：
/// <summary>
/// Converts a WPF RGB color to an HSL color
/// </summary>
/// <param name="rgbColor">The RGB color to convert.</param>
/// <returns>An HSL color object equivalent to the RGB color object passed in.</returns>
static HlsColor RgbToHls(Color rgbColor)
{
// Initialize result
var hlsColor = new HlsColor();
// Convert RGB values to percentages
double r = (double)rgbColor.R / 255;
var g = (double)rgbColor.G / 255;
var b = (double)rgbColor.B / 255;
var a = (double)rgbColor.A / 255;
// Find min and max RGB values
var min = Math.Min(r, Math.Min(g, b));
var max = Math.Max(r, Math.Max(g, b));
var delta = max - min;
/* If max and min are equal, that means we are dealing with
* a shade of gray. So we set H and S to zero, and L to either
* max or min (it doesn't matter which), and then we exit. */
//Special case: Gray
if (max == min)
{
hlsColor.H = 0;
hlsColor.S = 0;
hlsColor.L = max;
return hlsColor;
}
/* If we get to this point, we know we don't have a shade of gray. */
// Set L
hlsColor.L = (min + max) / 2;
// Set S
if(hlsColor.L < 0.5)
{
hlsColor.S = delta / (max + min);
}
else
{
hlsColor.S = delta / (2.0 - max - min);
}
// Set H
if (r == max) hlsColor.H = (g - b) / delta;
if (g == max) hlsColor.H = 2.0 + (b - r) / delta;
if (b == max) hlsColor.H = 4.0 + (r - g) / delta;
hlsColor.H *= 60;
if (hlsColor.H < 0) hlsColor.H += 360;
// Set A
hlsColor.A = a;
// Set return value
return hlsColor;
}
/// <summary>
/// Converts a WPF HSL color to an RGB color
/// </summary>
/// <param name="hlsColor">The HSL color to convert.</param>
/// <returns>An RGB color object equivalent to the HSL color object passed in.</returns>
static Color HlsToRgb(HlsColor hlsColor)
{
// Initialize result
var rgbColor = new Color();
/* If S = 0, that means we are dealing with a shade
* of gray. So, we set R, G, and B to L and exit. */
// Special case: Gray
if (hlsColor.S == 0)
{
rgbColor.R = (byte)(hlsColor.L * 255);
rgbColor.G = (byte)(hlsColor.L * 255);
rgbColor.B = (byte)(hlsColor.L * 255);
rgbColor.A = (byte)(hlsColor.A * 255);
return rgbColor;
}
double t1;
if (hlsColor.L < 0.5)
{
t1 = hlsColor.L*(1.0 + hlsColor.S);
}
else
{
t1 = hlsColor.L + hlsColor.S - (hlsColor.L * hlsColor.S);
}
var t2 = 2.0*hlsColor.L - t1;
// Convert H from degrees to a percentage
var h = hlsColor.H / 360;
// Set colors as percentage values
var tR = h + (1.0/3.0);
var r = SetColor(t1, t2, tR);
var tG = h;
var g = SetColor(t1, t2, tG);
var tB = h - (1.0 / 3.0);
var b = SetColor(t1, t2, tB);
// Assign colors to Color object
rgbColor.R = (byte)(r * 255);
rgbColor.G = (byte)(g * 255);
rgbColor.B = (byte)(b * 255);
rgbColor.A = (byte)(hlsColor.A * 255);
// Set return value
return rgbColor;
}
/// <summary>
/// Used by the HSL-to-RGB converter.
/// </summary>
/// <param name="t1">A temporary variable.</param>
/// <param name="t2">A temporary variable.</param>
/// <param name="t3">A temporary variable.</param>
/// <returns>An RGB color value, in decimal format.</returns>
private static double SetColor(double t1, double t2, double t3)
{
if (t3 < 0) t3 += 1.0;
if (t3 > 1) t3 -= 1.0;
double color;
if (6.0 * t3 < 1)
{
color = t2 + (t1 - t2) * 6.0 * t3;
}
else if(2.0 * t3 < 1)
{
color = t1;
}
else if(3.0*t3 < 2)
{
color = t2 + (t1 - t2) * ((2.0/3.0) - t3) * 6.0;
}
else
{
color = t2;
}
// Set return value
return color;
}